Don't disagree on the risk of aging poorly, but there was never in a million years a way the Leaf's were signing DR to a 4 year deal. This is like the people saying "Don't like trade protection, just don't give it out!" ignoring the fact that situation would 100% guarantee that you're never getting a UFA to sign/extend with your team long term.
IMO - this was a gamble, and Chayka was left some pretty crappy cards from Treliving. This is doing the best he could with what he had. If this goes poorly, so did probably everything else and the Leafs are no worse off.
Comparison of a TERRIBLE deal would be to when Bowman was the Hawks MG and traded a boatload of assets to CLM for Seth Jones during a rebuild. Hawks essentially sent Boquist (recently drafted 8OA), 2021 12th OA, and their 2022 1st (ended up being 6OA) for Seth Jones (removed some extra picks which essentially cancelled out). That's a TERRIBLE deal for a rebuilding Hawks team which hampered the team going forward. If the Leafs melt down, IMO they are no worse off with this deal.